The invention discloses an on-line monitoring system for a surgical room. The on-line monitoring system comprises a monitoring mechanism, a filtration mechanism and a control mechanism, the monitoringmechanism consists of a monitoring box, a support partition plate, a first partition plate, a second partition plate, a third partition plate, a fourth partition plate, a temperature sensor, a humidity sensor, a pressure sensor, a remote particle counter, an air inlet, a first one-way valve and an air feeding pipe, the support partition plate is fixedly mounted inside the monitoring box, the topof the support partition plate is fixedly connected with the second partition plate and the fourth partition plate, and the third partition plate is fixedly mounted at the position, between the secondpartition plate and the fourth partition plate, of the top of the inner wall of the monitoring box. The on-line monitoring system adopts a bus mode, centralized management is easy, clean parameters,namely the number of dust particles, the temperature, the humidity and the differential pressure value, of the surgical room are monitored in real time and stored, when system alarming occurs, the alarm occurring time, the alarm content, the alarm state and the like are recorded, subsystems of all systems are relatively independent, operating of the other subsystems of the surgical room is not affected when a certain subsystem of the surgical room breaks down.